Any studies on HS information retention after 10-20 years? College/University?

Our brains are designed to mostly only remember the information we need, and use. In other words, I want to see a study proving how useless so much of the shit they throw you in school is.

Trade schools all the way. Fuck this "well rounded" bullshit. I want to be prepared to succeed at life, not forced to know who won the battle of 1320, or write papers on why I came 5 times reading To Kill a Mockingbird.